Spring probe pins are also often referred to as Pogo™ pins. Pogo™ is a registered trademark of Xcerra Corporation in Norwood, Mass. A spring probe pin or Pogo™ pin is a device used in electronics to establish electrical connection between two circuits. Pogo™ pins are usually arranged in a dense array, connecting together many individual nodes of two circuits or circuit boards. Pogo™ pin connectors are commonly found in automatic test equipment (ATE) in the form of a bed of nails where they facilitate the formation of rapid, reliable, temporary, electrical connections to devices under test. A Pogo™ pin connector may contain just a few Pogo™ pins or may contain many hundreds of Pogo™ pins.
One type of packaged integrated circuit that Pogo™ pins are used to electrically test is a ball grid array (BGA) package 100 such as is shown in FIG. 1. An integrated circuit (IC) is packaged in the BGA package 100. An array of solder balls 102 which may vary from a few solder balls to greater than 500 solder balls provides electrical connection between the IC in the BGA package and the circuit board on which the BGA package is mounted.
A typical BGA Pogo™ pin connector design used to electrically test solder ball connections on a BGA package 100 is shown in FIG. 2A. A cup shaped solder ball receptacle 204 which is about half the diameter of the solder ball 220 or less is mounted on a Pogo™ pin plunger 202. The Pogo™ pin plunger 202 may be spring loaded to provide similar pressure to solder balls that may be of various diameters.
As shown in FIG. 2B during electrical testing of the BGA package 100, the cup shaped solder ball receptacle 204 on the BGA Pogo™ pin is lowered so that the rim of the cup shaped solder ball receptacle 204 comes into contact with and forms electrical contact to the solder ball 220 on the BGA package 100.
A second typical Pogo™ pin connector design used to electrically test solder ball connections on a BGA package 100 is illustrated in FIG. 3A. The rim of the cup shaped solder ball receptacle 304 in this design has a crown design with crown points 306 around the rim of the cup 304.
As shown in FIG. 3B during electrical testing of the BGA package 100, the cup shaped solder ball receptacle 304 on the BGA Pogo™ pin is lowered so that the crown points 306 on the rim of the cup shaped solder ball receptacle 304 form electrical contact with the solder ball 210 on the BGA package 100. The crown points 306 provide increased pressure against the solder balls 210 to provide more reliable electrical contact. This type of design may extend the interval that the BGA Pogo™ pin may be used before replacement.